Gas discharge tube with a movable baffle between the electrodes



Sept..29, 1970 v GREBER 3,531,687

GAS DISCHARGE TUBE WITH A MOVABLE BAFFLE BETWEEN THE ELECTRODES Filed Oct, 17, 1968 FIGJI':

INVENTOR.

United States Patent Oflice Patented Sept. 29, 1970 3,531,687 GAS DISCHARGE TUBE WITH A MOVABLE BAFFLE BETWEEN THE ELECTRODES Henry Greber, New York, N.Y. Filed Oct. 17, 1968, Ser. No. 768,358 Int. Cl. H01j17/14, 61/92; Hb 41/39 US. Cl. 315-309 4 Claims ABSTRACT OF THE DISCLOSURE This invention is related to gas discharge lamps, and in particularity to fluorescent lamps that can operate without ballasts. This is achieved by making the cross sectional area of the gas discharge tube, at one point, dependent on the current passing the lamp, and by dividing the discharge stream of the lamp into pairs of oppositely directed streamlets. When the current in the lamp grows, then the charged particles in the streamlets interfere with each other and reduce the current to its preset value. This value can also be achieved by reduction of the cross section of the tube passed by these streamlets. The preset value of the current can be adjusted, for dimming purposes, by changing the cross-sectional area of the discharge streamlets, by means such as solenoids or permanent magnets operable from outside the gas discharge tube.

The most important gas discharge lamp, that is the fluorescent lamp was created only about thirty years ago. Its first public appearance was in 1938 at Worlds Fair in New York. At first it was considered as a source of colored light, and as such was intended primarily for advertising. Soon, however, it was developed into a principal source of white light. Since that time about three billion dollars worth of fluorescent lamps were produced in this country. Todays yearly production of fluorescent lamps in the United States is about 250 millions of lamps, worth nearly 350 millions of dollars. Fluorescent lamps amount to about two-thirds of all light sources in this country, in which half of the homes are illuminated with this kind of lamps.

Why only two-thirds? Due to their high efliciency, fluorescent lights would have eliminated incandescent lamps a long time ago, if not for their handicap of requiring ballasts for their operation. The reason why a ballast must be used with any gas-discharge lamp, can be found in its runaway characteristic. If not limited by a ballastthat is a resistor or impedance-the current of a gas discharge lamp would grow beyond all bounds up to the destruction of the lamp.

But the ballast is a serious handicap. In addition to being expensive, complicating the installation and operation of gas discharge lamps, it is noisy and prevents the interchangeability of fluorescent with incandescent lamps. On top of all that, it is a source of considerable losses. These amount to about of the total energy consumed by the gas discharge lamp. Up to now, the disadvantages of the ballast have been taken in stride. The effort of the prior art has been primarily directed toward minimizing some of its disadvantages, such as its noise, the voltage drop caused by it and particularly toward improving of the poor power factor caused by it As can be seen from the preceding, the application of the gas discharge and particularly of the fluorescent lamp could be considerably boosted even without any improvement of its design, merely by modifying it so as to make the ballast superfluous for its operation. Consequently, it IS the purpose of this invention to do away with the ballast altogether, by providing a method and means to operate a gas discharge lamp without it.

Another purpose of this invention is to use the same method and means to control the light output of a gas discharge lamp, particularly for dimming purposes, such as used in theaters for example.

A further purpose of this invention is to use said method and means to adjust the light output of a gas discharge lamp, in order to meet the demand for illumination at the moment. For example, if gas discharge lamps are used in addition, as a supplement to daylight, the first should gradually increase their light output at davm, and decrease it in the same way at dusk.

A still further purpose of this invention is to use said method and means to control the thermionic current of gas filled electronic tubes, especially of thyratrons.

And finally, it is also a purpose of this invention to supply a device whose resistance can be controlled without causing losses in the circuit into which it is inserted.

All these purposes are achieved in this invention by two means which can be used in combination, or separately. The first means consists in changing the area through which the arc discharge passes at a given point of the tubular bulb of the lamp. This change can be brought about by automatic, or by manual means, the latter being operable, of course, from outside of said tubular bulb. The second means consist in divining the gas discharge stream into a multiplicity of pairs of streamlets, with the streamlets in each pair being directed against the other. Also in this means a variation of the area passed by the gas discharge stream is required for adjustment of the light output of the lamp.

The nature of this invention, the way in which the above inventive ideas are incorporated into practical design variations of this lamp, its further advantages and potentialities for different applications will become clear from this specification taken with reference to the accompanying drawing.

In this drawing, FIG. 1 is a partial longitudinal cross sectional view of a fluorescent lamp according to this invention. FIGS. 2, 3, and 4 are also partial longitudinal cross sectional views of different embodiments of this invention all three showing different ways of thermostatically controlling the cross sectional. area passed by the gas discharge arc.

In FIGS. 5 and 6 partial longitudinal cross sectional views of two diflerent embodiments of this fluorescent tube with constrictions in it are depicted.

FIGS. 7, 8 and 9 present elevational views of three different ways in which the arc discharges are led along curved paths.

-In FIGS. 10, 11, and 12 can be seen elevational views of gas discharge tubes so combined as to form the outlines of the letters Y, H and K respectively.

FIG. 13 shows an elevational view of a gas discharge lamp whose tubes arranged to form a pretzel-like shape.

In FIG. 14 can be seen the elevational view of a gas discharge lamp whose tubes are joined to form the outline of the letter X.

FIG. 15 depicts an elevational view of a gas discharge lamp whose tubes form a rectangular frame.

The tubes of the gas discharge lamp, whose elevational view is shown in FIG. 16, form the outline of the letter T.

Finally, the elevational view shown in FIG. 17 presents a gas discharge lamp whose tubes are joined to shape the outline of a triangle.

In consideration of the details of the above listed figures, it can be seen that the tubular bulb 1, shown partly in cross section and partly in elevation in FIG. 1, is terminated with the bases 2 and 3. Base 2 contains pins 4 and 5. Base 3 comprises pins 6 and 7. Tube 1 contains filament 8 mounted on stem 9. The ends of filament 8 are connected to the pins 4 and 5. Tube 1 also contains filament 10, shown somewhat diagrammatically for completeness of the scheme, but the stern on which filament 10 is mounted is omitted for simplicity. Conductors 11 and 12 connect pins 5 and 7, respectively, to starter 13, and conductors 14 and 15 connect pins 4 and 6 to the source of voltage 16, shown diagrammatically, feeding the lamp. It can be seen that tube 1 contains a cylindrical dome 17, made of glass and tapered at its upper end at which it has the opening 18. Spring 19, made of two bimetallic strips, is fastened to stem 9. To spring 19 is attached rod 20, which carries two umbrella shaped surfaces 21 and 22. At the base 2 is placed cylindrical coil 23, shown somewhat diagrammatically in cross section. The ends of this coil are connected by means of conductor 25 to adjustable resistance 26, which is linked, by means of conductor 27, to a source of control voltage 28. This source (28) is, by means of conductor 29, in metallic contact with the other end of cylindrical coil 23.

In the partly cross sectional and partly elevational view of FIG. 2, it is shown that glass tube 30 is provided with base 31 on its lower end, and with base 32 on its upper end. Base 31 contains pins 33 and 34, and base 32 is provided with pins 35 and 36. Stem 37 carries the filament 38, shown diagrammatically, and also carries the straps 39 and 40, which are made of different metals, and taken together constitute a bimetallic thermostat of the lamp. Both straps 39 and 40 are fastened to the circular glass plate 41, which acts like a gate of a valve placed inside tube 30.

Glass tube 42 shown, partly in elevation and partly in cross sectional view, in FIG. 3, is provided with the bases 43 and 44, having the pins 45, 46, and 47, 48, respectively. Filament 49 is mounted on the stem 50, which also carries the thermostatic element 51, consisting of two straps of different metals. Thermostatic element 51 supports the circular glass plate 52, serving as a valve gate inside tube 42.

In FIG. 4 is shown glass tube 53, in the same manner in which the glass tubes are shown in the preceding figures. Glass tube 53 is equipped with the bases 54 and 55, which have the pins 56, 57, and 58, 59, respectively. Stem supports filament 61 and bimetallic element 62, to which circular glass plate 63 is fastened. Birnetallic element 62 carries the heater winding 64 consisting of a few turns connected in series with filament 61, by means of conductors 65 and 66, to pins 56 and 57.

In the partly cross sectional and partly elevational view depicted in FIG. 5, it can be seen that the glass tube 67 has a double conic constriction 68. In this constriction is placed funnel 69 and funnel 70, both made of sheet metal covered with enamel, and connected with each other by means of metallic rod 71, also covered with enamel. The edge of funnel 69 is turned around to form a collar 72, which contains holes such as 73 and '74 spaced around the said circular collar 72. Similarly, the edge of funnel is folded around to form collar 75, which contains holes such as 76 and 77 along the periphery of said collar 75. In a manner analogous to that in the preceding figures, stem 78 carries filament 79. The bases 80 and 81 are provided with pins 82, 83, and 84, 85, respectively.

if At base is placed solenoid coil 86, and its connections are the same as those in FIG. 1.

The partly cross sectional and partly elevational view of FIG. 6, represents a glass tube 87, also having a double conic constriction 88, in which are placed two glass funnels 89, joined together at their vertices. At their wide openings the two funnels (89, 90) are provided with metallic hooks, such as 91, 92, 93, 94, respectively, uniformly spaced around the peripheries of the wider openings of said glass funnels 89, 90. These hooks 91, 92, 93 and 94, space the glass funnels 89 and 90 away from glass tube 87. As in the preceding figures, filament 95 is supported on stem 96. Bases 98 and 99 are equipped with pins 99, 180, and 101, 102, respectively.

In the elevational view of FIG. 7 it can be seen that tube sections 103 and 104 are connected with each other by means of the circular tube 105. Base 106 has the pins 107, 108, and base 109 has the pins 110, 111. It can be seen that charged particles flowing in the direction from base 106 to base 109 will be directed against each other as is indicated with the arrows 112 and 113.

In the elevational view of FIG. 8, tube sections 114 and 115 are connected by means of two circular tubes 116 and 117. Base 118 holds pins 119 and 120, and base 121 holds pins 122 and 123. It can be realized that charged particles flowing in the direction from base 118 toward 121 will be divided into two streams directed against each other. These streams will meet twice, as indicated with the pairs of arrows 124, 125, and 126, 127.

The lamp whose elevational view is shown in FIG. 9 has 'its tube sections 128, 129 connected by means of three elliptical tubes 130, 131, 132. In base 133 are mounted the pins 134, 135, whereas in base 136 are mounted the pins 137, 138. A stream of charged particles flowing in the direction from base 133 toward base 136 is divided into two parts which are directed against each other, and collide in points indicated with the pairs of arrows 139, 140, and 141, 142, and 143, 144.

In FIG. 9 is shown the elevational view of a gas discharge tube whose tube sections 145, 146 and 147 are joined to form the outline of the letter Y. The bases of this lamp, 148, 149 and 150 are provided with the pin pairs, 151, 152 and 153, 154, and 155, 156, respectively. The charged particle stream flowing in direction from base 148 toward base 149, is a part of a different electric circuit than the charged particle stream flowing in the direction from base 150 toward base 149. It can be realized that said two streams collide, as indicated with the arrows 157, 158.

It can be seen in the elevational view of FIG. 10 that the tubes 159, and 161 of the presented gas discharge lamp are so joined together as to form the outline of the letter H. The bases of the lamp: 162, 163, 164 and 165 carry the pin pairs: 166, 167, and 168, 169, and 170, 171, and 172, 173, respectively. Base 162 is connected in parallel with base 164, through the intermediary of their respective pin pairs 166-167, and 170-171. Likewise, bases 163 and 165 are connected in parallel, through the intermediary of their pin pairs: 168-169, and 172-173. However, the bases connected in parallel that is 162-164, and 163-165 are in opposite phase. In consequence of this connection a stream of charged particles flowing in the direction from base 162 to base 165, is directed in opposition to the stream of charged particles flowing in the direction from base 168 toward base 164. Said two streams, indicated by the arrows 174, 175 are opposed to each other along the entire tube 160.

Another variation of this scheme is shown in the elevational view of FIG. 12, in which the tubes 176, 177 and 178 of the composite gas discharge lamp are so joined as to form the outline to the letter K. Bases 179, 180, 181 and 182, are equipped with the pin paris: 183-184, 185-186, 187-188, and 189-190. The stream of charged particles flowing in the direction from base 179 toward base 182 is a part of one circuit, while the stream of charged particles flowing in the direction from base 180 toward base 181 is a part of another, independent cir- -cuit, both supplying the same composite gas discharge llamp. The first stream-in direction from base 179 to base 182-is indicated with arrow 191. The second stream-from base 180 to base 181-is indicated with arrow 192. It can be seen that the two streams collide at the crossover point of the tubes 176, 177 and 178.

A pretzel-like shape of a gas discharge tube, which also resembles the shape of the numeral 8 is shown in the elevational view presented in FIG. 13. There, the short section of the large diameter glass tubes 193 and 194 are joined together with the small diameter tube sections 195, 196, 197, and 198 to form the described shape. The bases 199 and 200 of the gas discharge lamp are provided with the pins pairs, 201-202, and 203-204, respectively. It can be visualized that the charged particle stream passing the lamp in in the direction from base 199 toward base 200 collide twice, as indicated with the arrow pairs 205-206, and 207-208.

The composite gas discharge lamp whose elevational view is drawn in FIG. 14, resemble-s the outline of the letter X. Its joined tubes 209, 210, 211, and 212 are terminated with the bases 213, 214, 215 and 216. These bases have the pin pairs, 217-218, 219-220, 221-222, 223-224, respectively. Bases 213 and 214 are connected in parallel and in the same phase relationship. In the same way, bases 215 and 216 are connected in parallel and these two are also in the same phase relationship. As a consequence of this arrangement, the stream of charged particles indicated with arrow 225, and flowing in the direction from base 213, toward 215, collides with the stream of charged particles, indicated with arrow 226 and flowing in the direction from base 214 toward base 216.

The glass tubes 227, 228, 229, 230, 231, 232 of the gas discharge lamp, whose elevational view is shown in FIG. 15, are joined together is such a way as to form a rectangular frame. The bases of the lamp, 233 and 234 are furnished with the pin pairs: 235-236, and 237-238, respectively. The are striking in the direction from base 233 toward base 234 is divided into two parts, as indicated with the arrows 239 and 240. They collide at the intersection of glass tubes 227 and 232.

In FIG. 16 can be seen an elevational view of a gas discharge lamp whose glass tubes 241, 242 are joined together to form the outline of the letter T. The bases 243, 244, 245 or this composite lamp are provided with the pin pairs: 246-247, 248-249, 250-251, respectively. The are between the bases 243-244 is a part of one electric circuit, while the are between the bases 243-245 is a part of another electric circuit independent from the first. Said are are indicated with the arrows 252, 253. It can be seen that the two arcs collide at the point of intersection of the tubes 241 and 242.

Finally, in FIG. 17 is shown the elevational view of a fluorescent lamps whose glass tubes 254, 255, 256, and 257 are joined together to form the outline of an equilateral triangle. The bases 258, 259 of this tube are provided with the pins pairs 260-261, and 262-263. An are striking in the direction from base 258 toward base 259 is divided into two partsalong tubes 255 and 257. These arcs collide at the point of intersection of tubes 255, 257, and 259, as indicated with the arrows 260, and 261.

All the design variations illustrated in the seventeen figures of the drawing, and described in the preceding part of this specification have the following features in common. They all have glass tubular bulbs containing mercury vapor at low pressure, with addition of a small amount of argon gas. The inner walls of the tubes are, as usually, coated with fluorescent phopshor powders. Electrons emitted by one filament electrode are attracted by the opposite electrode. On their way from one electrode to the other, the electrons collide with neutral mercury vapor molecules. The excited electrons in these molecules emit ultraviolet radiation which is converted by the phosphor powder into visbile light. The electrodes are presented as hot cathodes, that are usually made of coiled coils of tungsten wire. This ballastless gas dis charge lamp, however, can operate with any other type of electrodes, for example, with cold cathodes. All the types of lamps presented in the drawing are shown as of the preheat rapid start type. Such lamps require four electrical contacts for their operation, and have a bipin base at each end. In such lamps, the starter, usually a glow switch, completes the circuit and lets the heating curernt flow through both filament electrodes. When this switch is opened, an arc strikes between these electrodes. The complete connection diagram is shown only in FIG. 1, but is omitted in all subsequent figures, in order to avoid unnecessary repetition. It is to be understood. however, that this ballastless lamp can be provided with any other kind of base, in particularity, it can operate with one-pin bases, such as used, for example in instant start lamps. In these, by application of a sutficiently high voltage, an arc strikes between the electrodes, without their being preheated. In the drawing, bipin bases are shown on all lamps for the sake of greater generality.

As stated, this ballastless gas discharge lamp is based on two modes of operation which can be applied separately, or in combination. Their combination is illustrated in FIG. 1. The first mode of operation is that the arc is divided into pairs of arcs, with one are of the pair directed against the other are in the same pair. Should the current in the lamp grow beyond its preset limit, then the charged particles in one are of a pair interfere with the charged particles of the opposite arc of the same pair. As a consequence of this interference, the value of the current is reduced back to its preset value. The division of the gas discharge stream, that is of the arc, into one or more pairs, can be brought about by the simple means of splitting the large diameter glass tube into two of smaller diameters. This can be seen in FIGS. 7, 8, 9, 13, 15, and 17. In all these cases the arc starting from one electrode is split into two oppositely directed arcs. The same principle is also applied in FIGS. 1, 5, 6, except that the arc is divided into an infinite number of the arclets so that to each arclet at one point of the periphery of the tube corresponds an opposite arclet at the diametrically opposite point of the tube.

This principle of operation is fully suflicient for gas discharge lamps whose light output is to remain constant. Into this category fall the great majority of fluorescent lamps used in residential, industrial, commercial and institutional buildings. Said principle is not suflicient, however, as a mode of operation for gas discharge lamps whose light output must be adjusted to the demand for illumination at the moment. This pertains especially to lamps whose light must be dimmed, such are used in theaters.

In order to make the adjustment of the light output of a gas discharge lamp, and in particularity, to make its dimming possible, to said first principle of operation a second mode of functioning is added. This mode consists in providing inside the gas discharge tube valve means whose gate element can be opened or closed and thereby open or close the passage way of the gas discharge stream through the gate. As shown in FIGS. 1, 2, 3, 4, 5, and 6, this valve gate can be operated automatically, preferably by means of a thermostat, or manually. As already said, for the majority of fluorescent lamps used today, the auto matic mode of adjustment of gate means of the valve would be fully suflicient. But, for the minority of the lamps, whose light output must be controlled at will, the manual means of adjustment must be used. The automatic means of controlling the value of the current passing through the lamp will be described first. For this purpose, attention is directed to FIG. 2. There the gate of the valve is a circular glass plate 41, fastenend to stem 37 by means of two straps, 39, 40 made of diflferent metals. Should the current through the lamp grow, as it is bound to do, be-

plate connected with them will be hotter. One of the straps cause of its runway characteristic, the two straps and the will be elongated more than the other. As a consequence of this differential elongation, the circular plate 41 is turned and narrows down the passage way through the lamp. Such change cannot fail to reduce the current flowing through the lamp, which thus is kept at a constant value. This mode of operation is, obviously, of no avail for arbitrary adjustment of the value of the current flowing through the lamp. For such adjustment the electromagnet ic coil, 23, as shown in FIG. 1, must be applied to the lamp in FIG. 2. To apply this coil one of the strap, for example 40, must be made of a ferromagnetic material, such as iron, steel, nickel. When the coil 23 is energized, it attracts straps 40, and thus tilts the disc 41, thereby changing the passage way for the lamp, and with it, also the current passing the lamp. The automatic action of the thermostat will then maintain the value of the current at it new preset value.

From the aforegoing description it is apparent, that in order to solve the problem of ballastless operation of gas discharge lamps of all kinds, both principles must be used, since they reinforce and complement each other. Their combined operation can be seen in FIG. 1. Through the interrelation between dome 17 and the umbrella like surfaces 21, 22 the arc is divided into a multiplicity of arc pairs, each arclet of a pair being counterdirected to the other arclet of the same pair. This action is reinforced by varying the cross section between the dome 17, and the surfaces 21, 22, which is done by a spring 19 consisting of two straps of different metals, and therefore acts as a thermostat. These two control means would be fully sulficient for a lamp with constant light output. But for a lamp with adjustable light production, the energized coil 23 pulls down the umbrella shaped surfaces 21, 22 made of one of the ferromagnetic materials, and thereby changes the magnitude of the current passing through the lamp.

One or the other mode of operation, or their combination can be found in each of the presented embodiments of this ballastless gas discharge lamp. In particular, in FIG. 3, the two bimetallic strips are united into one double strap 51; and in FIG. 4, this united double strap, here designated with 62 is heated by means of a few heater windings 24, connected in series with filament 61. In FIG. 5, the control of the current of the lamp rests on counter directed gas discharge streams passing, for example through holes 76, and 77. For dimming, the two funnels 69, 70 made of ferromagnetic material, are pulled down by the energized coil 86, and thereby narrow the passage way of the gas discharge stream through the lamp. What was stated about FIG. 5 can be repeated for FIG. 6, except that the double funnel 8930 is made of glass, and the coil which is not shown to avoid repetition-would act on the hooks made of ferromagnetic metal, and through them would pull the double funnel down and thus narrow down the cross sectional area of the tube at the point of constriction of the tube. As stated already, while in FIGS. 7, 8, 9, 13, 15, and 17, the arc is divided into two counterdirected parts, the counterdirected arcs in FIGS. 10, 11, 12, 14, and 16, belong to different circuits, which are electrically separated.

This ballastless gas discharge, and particularly fluorescent lamp is intended primarly for application in residential, industrial, commercial, institutional and farm buildings in which an adjustment of the light output of the lamp is not required, that is the lamp is either on or off.

A second application of this ballastless gas discharge lamp, and especially fluorescent lamp is for installations in which the light output of the lamp is adjustable. As already described, in lamps used to supplement daylighting, it is desirable that the light output of the lamps be decreased gradually at dawn and increased in the same way at dusk. Street lighting may fall into this category. Another application of the controlled ballastless fluorescent lamp is where dimming is required, in theaters, auditoria, and the like.

The applicability of this invention, however, is not limited to lighting only. The same method and means can be used for controlling the current in electronic lamps. For example, a mercury rectifier tube provided with a split tube arrangement as per FIG. 13, for example, or other means described in this specification, can produce DC almost without ripples, and may require only a small capacitor and choke coil, if any, for smoothing of the current wave.

Similarly, the method and means described in this specification can be used for maintaining a constant current in other electronic tubes, such as thyratrons for example.

A gas discharge tube provided with means to control the magnitude of the current passing through it, according to this specification, can be used to control the resistance in a given electrical circuit, without incurring any additional losses in that circuit. For this purpose such ballastless lamp must be inserted in series into the controlled circuit, in which the value of the passing through it current is to be adjusted. This method may find its application is electrical circuits, feeding heaters, welders, electrical machines. The method can also be used to control the current in excitation circuits of DC machines, and of the rotor or stator currents in AC machines. It can find its application in voltage stabilizers used to feed voltage-sensitive loads, such as computer installations. This ballastless gas discharge lamp inserted into any electrical circuit can protect it against possible damage due to a short circuit, in it by keeping the current in this circuit under a preset value. Such scheme is particularly easy to actualize in high voltage circuits, in which the voltage drop in the gas discharge lamp is of no consequence.

Despite the many different applications of this invention that consisting in its use for fluorescent lamps is considered here to be the most important. For one thing, it would make fluorescent and incandescent lamps completely interchangeable, which is a much desirable goal. For another, more important thing, the deletion of the ballasts of fiuorescent lamps now used by the millions, would mean substantial savings not only in the purchase, installation and maintenance cost of the ballasts, but also in the cost of electric energy normally lost in them. It is hardly an exaggeration to state that these savings may well run into hundreds of millions of dollars per year for the United States alone.

As is apparent from the foregoing description, this invention can be applied in many different ways, and for many different purposes. Some of them have been indicated. Many more are possible by modification, variation, and changes of this invention, by addition, omission, or substitution of means used in it by equivalents, all within the meaning of this invention and within its scope as defined by the following claims.

I claim:

1. A ballastless gas discharge lamp, in particularity a fluorescent lamp comprising means for division of the gas discharge stream into a plurality of gas discharge stream pairs, each stream of a gas discharge pair being directed against the other stream of the pair, said gas discharge lamp also comprising valve means for reduction of the passageway of said gas discharge stream, said valve means being controllable from outside of the en closure of said gas discharge lamp.

2. A ballastless gas discharge lamp as in claim 1, in which the division of the total gas discharge stream into pairs, each consisting of two oppositely directed gas discharge streams, is accomplished by dividing its large diameter tube at its base into a plurality of small diameter tubes which are joined at least in one point between the two terminals of the lamp, said division of the gas stream of said lamp also being achieved by means of an hourglass shaped double funnel, forming a constriction in the tube of said gas discharge lamp, with the displacement of the internal funnel being accomplished by means 9 1O operable from outside of said gas discharge lamp. References Cited in;iii :$525211?iuilii ll fil fiiilfil311$ iii! UNITED STATES PATENTS which at change of their length due to temperature varia 193O132 10/1933 Reger 313 220 X tions, move said valve gate means, in addition said valve 2'906905 9/1959 Wares 313 186 X 5 2 908 841 10/1959 Gerber 313204 gate means can be controlled by means which are operable from outside of said gas discharge lamp. 32950O3 12/1966 Chermn 313 204 X 4. A ballastless gas discharge lamp as in claim 1 in 3482141 12/1969 Gerber 313 152 X which the electromechanical means operable from out- JAMES W, LAWRENCE, Primary Examin side of said gas discharge lamp and serving to move said 10 valve means placed inside said gas discharge means, are CAMPBELL Asslstant Exammer connected in series with said gas discharge lamp. US. Cl. X.R. 

